Target For Pulmonary Arterial Hypertension Research Articles

"Mendelian randomisation and experimental medicine approaches to interleukin-6 as a drug target in pulmonary arterial hypertension." Mark Toshner, Colin Church, Lars Harbaum, et al. Eur Respir J 2022; 59: 2002463.

"Mendelian randomisation and experimental medicine approaches to interleukin-6 as a drug target in pulmonary arterial hypertension." Mark Toshner, Colin Church, Lars Harbaum, et al. Eur Respir J 2022; 59: 2002463.

THERAPEUTIC EFFECTS OF NEBULIZATION- BASED DELIVERY OF ANTI-MIR-146A IN EXPERIMENTAL PULMONARY ARTERIAL HYPERTENSION

Objective: Pulmonary arterial hypertension (PAH), is a chronic disorder characterized by excessive pulmonary vascular remodelling, resulting in elevated pulmonary vascular resistance and right ventricle (RV) overload and failure. PAH remains incurable, and new therapeutic approaches are required. The microRNA-146a (miR-146a) promotes vascular smooth muscle cell proliferation and vascular neointimal hyperplasia, both important hallmarks of PAH. This study aimed to investigate the role of miR-146a in the pathophysiology of PAH and in the progression to RV hypertrophy and failure. Design and method: Sprague Dawley rats received a subcutaneous injection of monocrotaline (MCT group) or vehicle (CTRL group) and, after fourteen days they were treated, by intratracheal nebulization, with an anti-miR-146a, forming four distinct groups: CTRL-treated; CTRL-untreated, MCT-treated, and MCT-untreated. Twenty-seven days after MCT injection, echocardiographic and invasive hemodynamic evaluations were performed in all animal groups. Also, wild-type (WT) and miR-146a knock-out (KO) (miR-146a-/-) mice were submitted to either 3 weeks of chronic hypoxia-induced PAH with weekly Sugen 5416 administration (SuHx). Results: Compared to MCT-untreated rats, the MCT-treated rats showed decreased RV hypertrophy, (as measured by the Fulton index), decreased RV end-diastolic diameter/left ventricle end-diastolic diameter (RVEDD/LVEDD) ratio, and decreased in RV diastolic pressures. KO-SuHx group, when compared to WT-SuHx group, showed decreased RV hypertrophy (as measured by the Fulton index), and decreased RV systolic pressures and dilation, as well as lower RV end end-diastolic diameter (RVEDDi) and right atria area (RAAi). Conclusions: Our findings show that miR-146a pharmacological or genetic inhibition reduces RV remodelling and improves cardiac function. Thus, miR-146a represents a promising therapeutic target in PAH.

Outcome of mean pulmonary arterial pressure-based intensive treatment for patients with pulmonary arterial hypertension

BackgroundMean pulmonary arterial pressure (mPAP) has not been recognized as a therapeutic target for pulmonary arterial hypertension (PAH). However, previous reports demonstrated that the survival of patients with some types of pulmonary hypertension was associated with mPAP. Therefore, we treated all subsets of PAH patients with the aim of lowering mPAP and evaluated the efficacy of the treatment algorithm. MethodFrom September 2014 to August 2019, 43 consecutive patients with PAH on treatment <3 months on referral were enrolled in this study. They were treated according to our treatment algorithm mainly based on World Health Organization functional class, mPAP, and percent predicted diffusing capacity of the lung for carbon monoxide. The therapeutic goal was the achievement of mPAP <40 mmHg at follow-up. We evaluated clinical parameters, survival rate, and its determinants. Survival analyses were conducted using the Kaplan-Meier method and the relationship between all-cause death and selected variables was analyzed using the Cox proportional hazards model for mortality. ResultsmPAP significantly improved at the last follow-up [45 (35–55) mmHg to 24 (19–30) mmHg, p < 0.05], and the therapeutic goal was achieved in 37 patients (86%). The 5-year survival rate of all patients was 90.7%. The survival rate of patients who achieved the therapeutic goal (3- and 5-year survival: 97.3%) was significantly better than that of the patients who did not achieve the therapeutic goal (3-year survival: 50.0%, p < 0.05). The 5-year survival rates of the patients were the same among different treatment regimens (p = 0.985). mPAP <40 mmHg at follow-up was the independent predictor of survival. ConclusionsLowering mPAP resulted in favorable outcomes in all subsets of PAH patients, making it a therapeutic goal.

VPO1/HOCl/ERK pathway mediates the right ventricular remodeling in rats with hypoxic pulmonary hypertension

Right ventricular (RV) remodeling is a major feature of pulmonary arterial hypertension (PAH). Vascular peroxidase 1 (VPO1) is reported to participate in the process of PAH. This study aims to explore whether VPO1 contributes to hypoxia-induced cardiac hypertrophy and the underlying mechanisms. SD rats were exposure to continuous hypoxia (10% O2) for 3 weeks, which showed RV hypertrophy (increases in the ratio of RV weight to tibia length, cardiac cell size and hypertrophic markers), concomitant with upregulation of VPO1, elevation in hypochlorous acid (HOCl) production and ERK phosphorylation. In hypoxia (3% O2)-induced hypertrophic H9c2 cells, similar characteristics of cardiac hypertrophy to that of hypoxia-treated rats were observed. Administration of VPO1 siRNA or NaHS (the HOCl inhibitor) suppressed HOCl production, ERK phosphorylation, and cardiac hypertrophy. Replacement of hypoxia with NaClO (exogenous HOCl) could also induce cardiac cell hypertrophy and activate ERK signaling pathway. In addition, hypoxia-induced cardiac hypertrophy could be blocked by PD98059 (the ERK-specific inhibitor). Based on these observations, we conclude that VPO1 promotes RV remodeling in PAH rats through catalyzing HOCl production, leading to the activation of ERK signaling. Thus, VPO1 may have the potential as a therapeutic target for PAH.

SUR1 As a New Therapeutic Target for Pulmonary Arterial Hypertension.

Mutations in ABCC8 have been identified in pulmonary arterial hypertension (PAH). ABCC8 encodes SUR1, a regulatory subunit of the ATP-sensitive potassium channel Kir6.2. However, the pathophysiological role of the SUR1/Kir6.2 channel in PAH is unknown. We hypothesized that activation of SUR1 could be a novel potential target for PAH. We analyzed the expression of SUR1/Kir6.2 in the lungs and pulmonary artery (PA) in human PAH or experimental pulmonary hypertension (PH). The contribution of SUR1 in human or rat PA tone was evaluated, and we measured the consequences of invivo activation of SUR1 in control and PH rats. SUR1 and Kir6.2 protein expression was not reduced in the lungs or human pulmonary arterial endothelial cells and smooth muscle cells from PAH or experimentally induced PH. We showed that pharmacological activation of SUR1 by three different SUR1 activators (diazoxide, VU0071063, and NN414) leads to PA relaxation. Conversely, the inhibition of SUR1/Kir6.2 channels causes PA constriction. In vivo, long- and short-term activation of SUR1 with diazoxide reversed monocrotaline-induced PH in rats. In addition, invivo diazoxide application (short protocol) reduced the severity of PH in chronic-hypoxia rats. Moreover, 3 weeks of diazoxide exposure in control rats had no cardiovascular effects. Finally, invivo, activation of SUR1 with NN414 reduced monocrotaline-induced PH in rats. In PAH and experimental PH, the expression of SUR1/Kir6.2 was still present. In vivo pharmacological SUR1 activation by two different molecules alleviated experimental PH, providing proof of concept that SUR1 activation should be considered for PAH and evaluated more thoroughly.

Involvement of Orai1 Ca2+ channel in the pathogenesis of pulmonary arterial hypertension. Orai1 as a new potential therapeutic target?

The pathobiology of pulmonary arterial hypertension (PAH) involves pulmonary arterial smooth muscle cells (PASMCs) dysfunction leading to abnormal proliferation, apoptosis resistance and vasoconstriction. Store-operated Ca 2+ entry (SOCE) strongly contributes to Ca 2+ homeostasis in PASMCs, however, the role of SOCE archetype Orai1 Ca 2+ channel in PAH pathogenesis was unclear. To understand the role of Orai1, we used a combination of Ca 2+ imaging, molecular biology, in vitro, ex vivo and in vivo approaches. We also analyzed the consequence of in vivo pharmacological inhibition of Orai1 in two experimental PH models. We demonstrated that SOCE is increased in human PASMCs from patients with idiopathic PAH (iPAH). Pharmacological inhibition of Orai1 or Orai1 knockdown by siRNA reduced SOCE as well as aberrant proliferation, apoptosis resistance phenotype, exacerbated cell migration and exacerbated calcineurin activity in iPAH-PASMCs. We showed that pharmacological inhibition of Orai1 reduced the capacity of isolated human pulmonary arteries to constrict. In PH rat models induced by Monocrotaline (MCT) or Chronic-Hypoxia (CH) exposure, we found an overexpression of Orai1 in lung and isolated pulmonary arteries. Finally, we found that the in vivo pharmacological inhibition of Orai1 by three different blockers reduced experimental-PH (MCT and CH). Altogether our results provide proof of concept that Orai1 should be considered as a new therapeutic target in PAH.

Using the Plasma Proteome for Risk Stratifying Patients with Pulmonary Arterial Hypertension.

Rationale: NT-proBNP (N-terminal pro-brain natriuretic peptide), a biomarker of cardiac origin, is used to risk stratify patients with pulmonary arterial hypertension (PAH). Its limitations include poor sensitivity to early vascular pathology. Other biomarkers of vascular or systemic origin may also be useful in the management of PAH. Objectives: Identify prognostic proteins in PAH that complement NT-proBNP and clinical risk scores. Methods: An aptamer-based assay (SomaScan version 4) targeting 4,152 proteins was used to measure plasma proteins in patients with idiopathic, heritable, or drug-induced PAH from the UK National Cohort of PAH (n = 357) and the French EFORT (Evaluation of Prognostic Factors and Therapeutic Targets in PAH) study (n = 79). Prognostic proteins were identified in discovery-replication analyses of UK samples. Proteins independent of 6-minute-walk distance and NT-proBNP entered least absolute shrinkage and selection operator modeling, and the best combination in a single score was evaluated against clinical targets in EFORT. Measurements and Main Results: Thirty-one proteins robustly informed prognosis independent of NT-proBNP and 6-minute-walk distance in the UK cohort. A weighted combination score of six proteins was validated at baseline (5-yr mortality; area under the curve [AUC], 0.73; 95% confidence interval [CI], 0.63-0.85) and follow-up in EFORT (AUC, 0.84; 95% CI, 0.75-0.94; P = 9.96 × 10-6). The protein score risk stratified patients independent of established clinical targets and risk equations. The addition of the six-protein model score to NT-proBNP improved prediction of 5-year outcomes from AUC 0.762 (0.702-0.821) to 0.818 (0.767-0.869) by receiver operating characteristic analysis (P = 0.00426 for difference in AUC) in the UK replication and French samples combined. Conclusions: The plasma proteome informs prognosis beyond established factors in PAH and may provide a more sensitive measure of therapeutic response.

Caspase-4/11-Mediated Pulmonary Artery Endothelial Cell Pyroptosis Contributes to Pulmonary Arterial Hypertension.

Endothelial dysfunction enhances vascular inflammation, which initiates pulmonary arterial hypertension (PAH) pathogenesis, further induces vascular remodeling and right ventricular failure. Activation of inflammatory caspases is an important initial event at the onset of pyroptosis. Studies have shown that caspase-1-mediated pyroptosis has played a crucial role in the pathogenesis of PAH. However, the role of caspase-11, another inflammatory caspase, remains to be elucidated. Therefore, the purpose of this study was to clarify the role of caspase-11 in the development of PAH and its mechanism on endothelial cell function. The role of caspase-11 in the progression of PAH and vascular remodeling was assessed in vivo. In vitro, the effect of caspase-4 silencing on the human pulmonary arterial endothelial cells pyroptosis was determined. We confirmed that caspase-11 and its human homolog caspase-4 were activated in PAH animal models and TNF (tumor necrosis factor)-α-induced human pulmonary arterial endothelial cells. Caspase-11-/- relieved right ventricular systolic pressure, right ventricle hypertrophy, and vascular remodeling in Sugen-5416 combined with chronic hypoxia mice model. Meanwhile, pharmacological inhibition of caspase-11 with wedelolactone exhibited alleviated development of PAH on the monocrotaline-induced rat model. Moreover, knockdown of caspase-4 repressed the onset of TNF-α-induced pyroptosis in human pulmonary arterial endothelial cells and inhibited the activation of pyroptosis effector GSDMD (gasdermin D) and GSDME (gasdermin E). These observations identified the critical role of caspase-4/11 in the pyroptosis pathway to modulate pulmonary vascular dysfunction and accelerate the progression of PAH. Our findings provide a potential diagnostic and therapeutic target in PAH.

Effects of microRNAs in hypertension disease

Hypertension is a cardiovascular disease which is a very common hemodynamic syndrome, and it has different prevalence in different regions as it is common all over the world. In recent studies, it is known that microRNAs (miRNAs) play an important role in hypertension disease and that miRNA expressions are regulated by epigenetic mechanisms. There are also studies proving that microRNAs are new therapeutic targets for pulmonary arterial hypertension, and miRNAs can participate in the pathophysiology of hypertension in many ways and it can be used as a biomarker for hypertension disease. It is thought that miRNAs can be effective in the diagnosis and treatment of hypertension and further studies are needed. Recently, the relationship between miRNAs and hypoxia has also been focused on and has been taken into account in studies. In this review, we aimed to present the effects of miRNAs on hypertensive disease and current approaches. Finally, with gene targeting studies, we think that miRNAs, which can be biomarkers and molecular agents, will hold promise in preventing the progression of hypertension in the future, and we hope that they can create ideas for future studies.

Potential of the TRPM7 channel as a novel therapeutic target for pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is an intractable vascular disease characterized by a progressive increase in pulmonary vascular resistance caused by pulmonary vascular remodeling, which ultimately leads to right-sided heart failure. PAH remains incurable, despite the development of PAH-targeted therapeutics centered on pulmonary artery relaxants. It is necessary to identify the target molecules that contribute to pulmonary artery remodeling. Transient receptor potential (TRP) channels have been suggested to modulate pulmonary artery remodeling. Our study focused on the transient receptor potential ion channel subfamily M, member 7, or the TRPM7 channel, which modulates endothelial-to-mesenchymal transition and smooth muscle proliferation in the pulmonary artery. In this review, we summarize the role and expression profile of TRPM7 channels in PAH progression and discuss TRPM7 channels as possible therapeutic targets. In addition, we discuss the therapeutic effect of a Chinese herbal medicine, Ophiocordyceps sinensis (OCS), on PAH progression, which partly involves TRPM7 inhibition.

Abstract 12681: Implication of Aurora Kinase B in Pulmonary Arterial Hypertension

Objective: Pulmonary arterial hypertension (PAH) is a vascular disease characterized by a progressive remodelling of pulmonary arteries (PAs). This leads to an elevation in PA pressure and resistance, leading to right heart failure and death. Nowadays, it is recognized that PA smooth muscle cells (PASMCs) are key actors in the histopathological changes in PAH. As seen in cancer cells, PASMCs exhibit a pro-proliferative and anti-apoptotic cancer-like phenotype, sustained by an important metabolic switch known as Warburg effect. Aurora kinase B (AURKB) is strongly involved in cell proliferation, apoptosis and metabolism by controlling cell cycle activation and mitochondrial functions. Previous research has shown that AURKB is overexpressed in various human cancers and its inhibition repressed tumor progression both in vivo and in vitro, suggesting that it could be a novel therapeutic target in PAH. We thus hypothesized that AURKB is upregulated in PAH and contributes to PAH-PASMCs proliferation and resistance to apoptosis, inhibition of which may reverse PA remodeling. Methods/Results: Using Western blot (WB), we demonstrated a FOXM1-dependent upregulation of AURKB in PASMCs isolated from PAH patients compared to controls (p&lt;0.05 ; n=8-14). Similar results were found in the monocrotaline (MCT) and sugen-hypoxia (Su/Hx) rat models (p&lt;0.05 ; n=11-22). In vitro, we found that pharmacological inhibition of AURKB significantly decreases PAH-PASMC proliferation (EdU incorporation, Ki67 labeling) as well as resistance to apoptosis (Annexin V assay) (p&lt;0.05 ; n=6). We also demonstrated that inhibition of AURKB decreases pro-survival factors such as Survivin and PLK1 and increases apoptosis and cell cycle arrest factors including P21, P27, and P53 (WB; p&lt;0.05 ; n=6). As expected, inhibition of AURKB in PAH-PASMCs was associated with a dose-dependent decrease of phosphohistone H3 expression, a well-known target of AURKB (p&lt;0.05 ; n=6). The therapeutic potential of Barasertib, a clinically available and specific AURKB inhibitor, is currently investigated in both MCT and Su/Hx models. Conclusion: Our preliminary data suggests the contribution of AURKB in PA remodeling and the great potential of using AURKB inhibitors to reverse PAH development.

Abstract 9512: Involvement of Orai1 Ca 2+ Channel in the Pathogenesis of Pulmonary Arterial Hypertension. Orai1 as a New Potential Therapeutic Target?

Introduction: Pulmonary arterial hypertension (PAH) is a devastating disease, characterized by a progressive obstruction of distal pulmonary artery (PA) leading to right ventricular hypertrophy and failure. Exacerbated intracellular Ca 2+ signalling contributes to functional abnormalities in pulmonary arterial smooth muscle cells (PASMCs), including aberrant proliferation, apoptosis resistance, exacerbated migration and pulmonary artery contractility. The role of archetypal Store-Operated Ca 2+ entry (SOCE) Orai1 Ca 2+ channel in PAH pathogenesis is unclear. Methods: Using a combination of Ca 2+ imaging, molecular biology, in vitro , ex vivo and in vivo approaches, we decipher the role of Orai1 Ca 2+ channel in pulmonary artery remodelling in PAH. We also analyzed the consequence of in vivo pharmacological inhibition of Orai1 in experimental models of PH. Results: We demonstrated that SOCE is increased in human PASMCs (hPASMCs) from patients with idiopathic PAH (iPAH) associated with an increased expression of Orai1 at mRNA and protein levels. Moreover, in vitro in iPAH-hPASMCs the pharmacological inhibition of Orai1 (by two different inhibitors) or the knockdown of Orai1 by siRNA reduced the SOCE as well as aberrant proliferation, apoptosis resistance phenotype and exacerbated cell migration. In addition, Orai1 knockdown reduced the exacerbated calcineurin activity in iPAH-hPASMCs. Using myograph experiments on isolated human and rat PAs we showed that pharmacological inhibition of Orai1 channels reduced the capacity of PAs to constrict. In rat experimental PH induced by Monocrotaline (MCT)-exposure or by Chronic-Hypoxia (CH) we found an overexpression of Orai1. Finally, in vivo pharmacological inhibition of Orai1 by three different blockers (BTP2, JPIII and 5J4) reduced experimental-PH in these experimental PH-models. Conclusion: In human PAH and experimental PH, the expression of Orai1 is increased compared to controls. In vitro and in vivo inhibition of Orai1 normalize the PAH phenotype of cultured iPAH-hPASMCs and reduce experimental-PH (MCT and CH). These results provide proof of concept that Orai1 contributes to PAH pathogenesis and that pharmacological inhibition of Orai1 should be considered as a new therapeutic target in PAH.

Abstract 13046: ALDH2-Mediated 4-HNE Contributes the Pathogenesis of Pulmonary Arterial Hypertension in Atherosclerotic Mice

Introduction: A high residual mortality for patients with pulmonary arterial hypertension (PAH) in this PAH-targeted therapy era implies the existence of untargeted pathways. High fat diet-fed ApoE knockout mice were found to develop PAH phenotype. Monocrotaline (MCT)-induced PAH rats also express high levels of 4-hydroxynenonal (4-HNE), a lipid peroxidation related aldehyde, in pulmonary vessels. Aldehyde dehydrogenase-2 (ALDH2), an important enzyme responsible for the removal of 4-HNE, is functionally defective near 50% of East Asians. Whether 4-HNE and its cognate detox enzyme ALDH2 participate in lipid dysregulation-induced PAH remains poorly understood. Methods and Results: Compared with ApoE knockout mice fed with normal chow, those with Piagen diet developed hypercholesterolemia, higher right ventricular systolic pressure (RVSP), and higher Fulton index (RV hypertrophy). Atherosclerotic plaques were widely distributed in the entire major arteries as well as pulmonary arteries. The lung tissue of Paigen diet-fed mice had higher levels of ALDH2 protein but lower levels of ALDH2 enzymatic activity, which was negatively associated with serum 4-HNE levels. Importantly, lung ALDH2 activities were negatively (R= -0.829, P=0.041), and serum 4-HNE levels positively (R=0.936, P=0.006) associated with RVSP. This data suggests that, in our model, ALDH2 expression may be upregulated to counteract but still exhausted by the high levels of lipid peroxidation products, such as 4-HNE. Conclusions: This data suggests that lipid dysregulation related 4-HNE/ALDH2 imbalance, at least in part, participates in PAH development and may potentially serve as a novel PAH target, particularly for East Asian people.

Abstract 12932: An Epigenetic Upregulation of Dynamin 2, a Regulator of Mitochondrial Fission, Promotes Human and Experimental Pulmonary Arterial Hypertension

Introduction: Increase in mitotic fission in pulmonary arterial smooth muscle cells (PASMC) contributes to the obstructive vasculopathy in pulmonary arterial hypertension (PAH). PAH’s fissogenic phenotype is due, in part, to excessive mitochondrial fission caused by activation of dynamin related protein-1 (Drp1). Recent observation suggests that to complete mitochondrial fission, Drp1 requires assistance from the GTPase dynamin 2 (DNM2). In this study we explore the role of DNM2 in the pathogenesis of PAH. Hypothesis: In PAH, increased expression of DNM2 increases mitochondrial fission and proliferation of PASMC. Methods: Immunoblot was used to quantify the expression of DNM2 in control (n=4) and PAH PASMC (n=5). Immunofluorescence was used to quantify the expression of DNM2 in the pulmonary arteries of monocrotaline (MCT) vs control rats. Flow cytometry was used to assess the effects of manipulating the expression of DNM2 on cell proliferation, cell cycle progression and rates of unstimulated apoptosis. Mitochondrial network structure was assessed using confocal imaging of cells infected with Adv-TOM20 mNeon green. Results: The expression of DNM2 was increased in human PAH PASMC vs control PASMC. Increase in the expression of DNM2 expression was also observed in the pulmonary arteries of MCT-PAH rats. Silencing DNM2 inhibited mitochondrial fission in PAH PASMC. Furthermore, silencing DNM2 inhibited proliferation in PAH PASMC by blocking the cell cycle at G1/G0. Conversely, augmenting DNM2 in normal PASMC induced mitochondrial fission and accelerated cell proliferation, recapitulating the PAH phenotype. In silico analysis identified miR-124-3p as a putative negative regulator of DNM2. Augmenting miR-124-3p decreased DNM2 expression, inhibited proliferation and induced apoptosis in PAH PASMC. Conclusion: DNM2 promotes mitochondrial fission and regulates cell proliferation in human PAH PASMC. Decreased miR-124-3p expression may contribute to upregulation of DNM2 in PAH. This work highlights the importance of DNM2 as partner with Drp1 in regulation of mitochondrial fission and shows that like Drp1, DNM2 is increased in human PAH. DNM2 may constitute new therapeutic target for PAH.

Osthole alleviates pulmonary vascular remodeling by modulating microRNA-22–3p mediated lipid metabolic reprogramming

BackgroundPulmonary vascular remodeling is the key pathological feature of pulmonary arterial hypertension (PAH) characterized by a pattern of lipid-related insulin resistance(IR), hormonal derangements and metabolic reprogramming. Our previous studies have demonstrated osthole as natural coumarin compound derived from traditional Chinese medicine is a promising agent for the treatment of pulmonary vascular remodeling in PAH. PurposeThe present study sought to delineate lipid metabolic modulatory mechanism of osthole against pulmonary vascular remodeling by employing an interdisciplinary strategy. MethodsRat model with PAH induced with MCT and PASMCs proliferation model induced with PDGF-BB were established in this study. Serum and lung tissues were used to lipid-related IR, hormone related indexes, pulmonary vascular remodeling analysis. Then, lipid metabolic gene, key enzymes, metabolites and cell proliferation indexes were examined to investigate metabolic regulatory mechanism in vivo and vitro model of PAH. ResultsOsthole significantly showed improvement of lipid-related IR and hormone dysregulation in rats with PAH evidenced by elevating testosterone, androgen receptor and cyclic guanosine monophosphate (cGMP), inhibiting phosphodiesterase-5(PDE-5), modulating lipid-related IR indexes total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), triglyceride (TG)/HDL-C ratio. Additionally, osthole limited key metabolic gene and enzymes to inhibit accumulation of decadienyl-l-carnitine in lipid metabolism, thus to promote oxidative phosphorylation and ATP production through inhibition of miRNA-22–3p, fatty acid translocase (CD36), fatty acid synthase (FAS), phospholipase A2 (PLA2), carnitine palmitoyltransferase 1A (CPT1A), hexokinase 2 (HK2), activation of metabolic switch isocitrate dehydrogenase 3α (IDH3α), NADH dehydrogenase 1 (ND1). We found for the first time miRNA-22–3p modulated PASMCs proliferation and vascular remodeling by regulating lipid metabolism reprogramming. Those modifications uncovered therapeutic mechanism of osthole against pulmonary vascular remodeling. ConclusionOur findings revealed the function of miRNA-22–3p in PASMCs and demonstrated a novel mechanism that miRNA-22–3p as a regulator can be targeted by osthole to greatly restore dysregulated lipid metabolism thus to alleviate pulmonary vascular remodeling in PAH, which provides novel insight into the potential therapeutic target for PAH, further highlights the development potential of osthole derived new drug against PAH.

Role of the Purinergic P2Y2 Receptor in Pulmonary Hypertension.

Pulmonary arterial hypertension (PAH), group 1 pulmonary hypertension (PH), is a fatal disease that is characterized by vasoconstriction, increased pressure in the pulmonary arteries, and right heart failure. PAH can be described by abnormal vascular remodeling, hyperproliferation in the vasculature, endothelial cell dysfunction, and vascular tone dysregulation. The disease pathomechanisms, however, are as yet not fully understood at the molecular level. Purinergic receptors P2Y within the G-protein-coupled receptor family play a major role in fluid shear stress transduction, proliferation, migration, and vascular tone regulation in systemic circulation, but less is known about their contribution in PAH. Hence, studies that focus on purinergic signaling are of great importance for the identification of new therapeutic targets in PAH. Interestingly, the role of P2Y2 receptors has not yet been sufficiently studied in PAH, whereas the relevance of other P2Ys as drug targets for PAH was shown using specific agonists or antagonists. In this review, we will shed light on P2Y receptors and focus more on the P2Y2 receptor as a potential novel player in PAH and as a new therapeutic target for disease management.

Mendelian randomisation and experimental medicine approaches to interleukin-6 as a drug target in pulmonary arterial hypertension.

BackgroundInflammation and dysregulated immunity are important in the development of pulmonary arterial hypertension (PAH). Compelling preclinical data supports the therapeutic blockade of interleukin-6 (IL-6) signalling.MethodsWe conducted a phase 2 open-label study of intravenous tocilizumab (8 mg·kg−1) over 6 months in patients with group 1 PAH. Co-primary end-points were safety, defined by incidence and severity of adverse events, and change in pulmonary vascular resistance. Separately, a mendelian randomisation study was undertaken on 11 744 individuals with European ancestry including 2085 patients with idiopathic/heritable disease for the IL-6 receptor (IL6R) variant (rs7529229), known to associate with circulating IL-6R levels.ResultsWe recruited 29 patients (male/female 10/19; mean±sd age 54.9±11.4 years). Of these, 19 had heritable/idiopathic PAH and 10 had connective tissue disease-associated PAH. Six were withdrawn prior to drug administration; 23 patients received at least one dose of tocilizumab. Tocilizumab was discontinued in four patients owing to serious adverse events. There were no deaths. Despite evidence of target engagement in plasma IL-6 and C-reactive protein levels, both intention-to-treat and modified intention-to-treat analyses demonstrated no change in pulmonary vascular resistance. Inflammatory markers did not predict treatment response. Mendelian randomisation did not support an effect of the lead IL6R variant on risk of PAH (OR 0.99, p=0.88).ConclusionAdverse events were consistent with the known safety profile of tocilizumab. Tocilizumab did not show any consistent treatment effect.

Novel Pharmacological Targets for Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a rare disease characterized by an obliterative vasculopathy of the distal pulmonary circulation that results in severe elevation in pulmonary pressure and pulmonary vascular resistance. PAH is a progressive and devastating disease that usually results in right heart failure and death. Currently available medications have only moderate effects and none are curative. Thus, there is a pressing need for new pharmacologic approaches to this disease. In order to meaningfully advance the treatment of PAH, new agents must target the underlying cause of disease induction and progression. This review discusses the extensive work that has been done in the areas of altered glucose metabolism, tyrosine kinase inhibitions, signaling pathways associated with disease causing gene mutations such as the bone morphogenic protein receptor 2, and inflammation and immunomodulation including the effects of mesenchymal stem cells and the extracellular vesicles they secrete. Epigenetic modifications including the roles of micro RNAs, DNA methylation, histone acetylation and transcription factors that modulate pulmonary vascular remodeling are also reviewed. A brief background of each area of interest is provided with emphasis on those components that have potential to be exploited for the treatment of PAH. Significant findings of cell-based and animal studies and, where available, the results of early clinical trials, are presented to illustrate the potential of these novel therapeutic targets. Current challenges to the development of small peptides and biologicals for the treatment of PAH and direction for future studies are also briefly discussed. © 2021 American Physiological Society. Compr Physiol 11:1-53, 2021.

NEAT1 silencing alleviates pulmonary arterial smooth muscle cell migration and proliferation under hypoxia through regulation of miR‑34a‑5p/KLF4 invitro.

Pulmonary arterial hypertension (PAH) is a severe vascular disease that adversely affects patient health and can be life threatening. The present study aimed to investigate the detailed role of nuclear paraspeckle assembly transcript1 (NEAT1) in PAH. Using RT‑qPCR, the expression levels of NEAT1, microRNA (miR)‑34a‑5p, and Krüppel‑like factor4 (KLF4) were detected in both hypoxia‑treated pulmonary arterial smooth muscle cells (PASMCs) and serum from PAH patients. Then, the interactions among miR‑34a‑5p, NEAT1, and KLF4 were evaluated by dual‑luciferase reporter assay. The detailed role of the NEAT1/miR‑34a‑5p/KLF4 axis in PAH pathogenesis was further explored using MTT, Transwell, and western blot assays. The results revealed that NEAT1 targeted miR‑34a‑5p and miR‑34a‑5p targeted KLF4. In hypoxia‑treated PASMCs and serum from PAH patients, high NEAT1 and KLF4 expression levels and low miR‑34a‑5p expression were observed. The proliferation and migration of hypoxia‑treated PASMCs were reduced by transfection with sh‑NEAT1 or miR‑34a‑5p mimics. The suppressive effects of NEAT1 knockdown on the proliferation and migration of hypoxia‑treated PASMCs were reversed by knock down of miR‑34a‑5p expression and increased KLF4 expression. NEAT1 was not only highly expressed in the serum of PAH patients but its silencing also alleviated PAH by regulating miR‑34a‑5p/KLF4 invitro. The present study highlighted a potential new therapeutic target and diagnostic biomarker for PAH.

Integrated Bioinformatics Analysis Reveals Marker Genes and Potential Therapeutic Targets for Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a rare cardiovascular disease with very high mortality rate. The currently available therapeutic strategies, which improve symptoms, cannot fundamentally reverse the condition. Thus, new therapeutic strategies need to be established. Our research analyzed three microarray datasets of lung tissues from human PAH samples retrieved from the Gene Expression Omnibus (GEO) database. We combined two datasets for subsequent analyses, with the batch effects removed. In the merged dataset, 542 DEGs were identified and the key module relevant to PAH was selected using WGCNA. GO and KEGG analyses of DEGs and the key module indicated that the pre-ribosome, ribosome biogenesis, centriole, ATPase activity, helicase activity, hypertrophic cardiomyopathy, melanoma, and dilated cardiomyopathy pathways are involved in PAH. With the filtering standard (|MM| > 0.95 and |GS| > 0.90), 70 hub genes were identified. Subsequently, five candidate marker genes (CDC5L, AP3B1, ZFYVE16, DDX46, and PHAX) in the key module were found through overlapping with the top thirty genes calculated by two different methods in CytoHubb. Two of them (CDC5L and DDX46) were found to be significantly upregulated both in the merged dataset and the validating dataset in PAH patients. Meanwhile, expression of the selected genes in lung from PAH chicken measured by qRT-PCR and the ROC curve analyses further verified the potential marker genes’ predictive value for PAH. In conclusion, CDC5L and DDX46 may be marker genes and potential therapeutic targets for PAH.